Horizontal coke oven method



Feb. 28, 1950 J. BECKER nonxzou'm. com: ovsn mmon Filed Aug. 30, 1

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Patented Feb. 28 1950 HORIZONTAL COKE OVEN METHOD Joseph Becker,Pittsburgh, Pa., assignor to Koppers Company, Inc., a corporation ofDelaware Application August 30, 1947, Serial No. 771,469

5 Claims.

in horizontal coke ovens and particularly to improvements in'theconformation of their cokingchambers whereby known operatingdiiilculties and their efiects on oven-operations and operating resultsare made less considerable even in those instances where such problemsare not en+ tirely solved by the instant improvements.

More particularly the present invention is directed to the method ofcoking coal in horizontal coke ovens described in my copendingapplication, Serial No. 562,442, filed November 8, 1944, now Patent2,447,837, of which this application is a division. v

In th art of coking coals and especially highvolatile coals at hightemperatures and fast coking-times in horizontal coke ovens, one of theonerous operating problems that can present itself is that ofmaintaining the roofs and the upper side-walls of the coking-chamberssubstantially free of so-called roof-carbon," i. e., accreted hardcarbonthat gradually accumulates on the masonry of the coking-chamber roofsand the upper side-walls and requires their frequent policing for itsremoval in order that the space of the gas-collecting space, provided ineach coking-chamber between its roof and the top of the coal charge,does not become so charged with said "roof-carbon that its capacity isimportantly reduced and the layer of charged coal that is at the top ofthe oven-charge, and which normally forms the bottom of saidgas-collectin space, does not become narrower than the ovencharges lowerpart. In the event such circumstance arises, the upper part of theoven-charge will be completely coked long before the cokingreaction haspenetrated through the remainder because less'than the normal amount ofcoal will be present there for carbonization by the heat radiateddirectly thereto through said gascollecting space from the surroundinghot masonry. Such condition occasions overheating of the tops of theoven-charges while trying to coke the remainder thereof and is conduciveto production of the phenomenon known as hottops, and this condition inthe coking chambers causes in turn excessive cracking of the gases andvapors evolved from the coking coal, thus aggravating the formation ofroof-carbon and also reducing the potential yield of valuable liquidbyproducts, such as phenols, and the like. If, therefore, the heatingconditions, for any reason required of employment in vertically walledcoking-chambers of coke ovens of the prior art, have a tendency becauseof the behavior of the employed coal to occasion deposition ofroofcarbon, its formation can become acceleratedly aggravated in avicious cycle that canchange the nature and amounts of recoveredbyproducts. Manifestly, the provision of simple means wherebydevelopment of the above-described phenomena in horizontal coke ovenscan be importantly inhibited or substantially eliminated will be a,distinct contribution to the available apparatus of the byproduct cokingart.

An object of the present invention is therefore the provision for ahorizontal coke oven of a substantially vertically-walled coking-chamberthat is adapted automatically to inhibit the formation of I roof-carbon"in the gas-collecting space of said oven and to avoid the deleteriousoperating effects and results its presence therein engenders.

A further object of invention is the provision ,of novel features ofdesign whereby cokingchambers of horizontal coke ovens that are equippedtherewith are advantageously operative with lower temperatures in thegas-collecting spaces than are like coking-chambers unequipped with saidnovel features.

A further object of invention is the provision of novel substantiallyvertically-walled cokingchambers for horizontal coke ovens wherebypenetration of the coking reaction completely through the upper parts ofthe coking-chamber charges of coal is automatically delayed until afterthe lower parts of said charges are coked and whereby the thickness ofthose horizontally extending seams of the fused coal that form in thetop of said charges are automatically maintained of easier apparentpenetrability, and consequently offer less resistance to escape of gasesand vapor from the interior of said charges than do those fused-coalseams that simultaneously form therein adjacent to and extend inparallelism with the sides and bottoms of the cokingchambers, so thatthe pressure of the coking charges of coal against the heating-walls ismade less than would otherwise obtain.

zontal coke ovens are provided with cokingchambers of which the heatedside-walls are throughout substantially their entire height verticallydisposed but, in contrast to horizontal coke ovens of the prior art, theupper minor portion of each said side-wall, from a level adjacent thehorizontal flue of the heating flue system, or its structuralequivalent, is disposed in a vertical plane remoter from thelongitudinal center of the coking-chamber than is the lower majorportion of said heated side-wall thereby forming in combination with itsopposite similarly formed side-wall a coking-chamber which iswider'adjacent its top than throughout the greater part of its height. Avertical section taken crosswise of the coking-chamber of inventionexhibits a contour similar to that of a capitaled pillar. The inventionalso preferably provides for use in combination with the abovedescribedinvention a pusher-side coke-oven door of which the lower edge of theleveller-door is above the horizontal level of the juncture between theupper wider and lower narrower parts of the associated coking-chamber sothat the top of a levelled coal-charge will present to thegas-collecting space a surface of coal that is wider than would obtainwere the top of the levelled coal-charge restricted to the narrowerportion of the instant coking-chamber, although even in the latterinstance some, but not all, of

the utility of the present novel construction can be enjoyed because ofthe greater capacity of the wider gas-collecting space to accumulateroofcarbon without restricting the expanse of coal that is directlyexposed near the top of the ovencharge to coking-heat radiated thereonfrom the masonry of the coking-chamber roof and the upper side-walls.The many benefits that accrue from employment of the present innovationin horizonal coke-oven design will be more easily appreciated byreference to the accompanying drawings and the hereinafter-givendiscussion thereof.

In the accompanying drawings forming a part of this specification andshowing for purposes of exemplification a preferred apparatus and methodin which the invention may be embodied and practiced but withoutlimiting the claimed invention specifically to such illustrativeinstance or instances:

Fig. 1 is a view showing a vertical section taken longitudinally througha coking chamber of the horizontal coke-oven battery of Fig. 2 embodyingthe present improvement and is taken along the line I-I of said figure;and

Fig. 2 is a view showing a vertical section taken longitudinally, alongthe line IIlI, of the battery of Becker-type horizontal coke ovens ofFig. 1 provided with the present improvement in coking chambers.

The same characters of reference designate the same parts in each of theviews of the drawings.

Referring now to the drawings: the coke-oven battery shown in the viewsof the figures and embodying features of the present improvement is ofthe well-known Becker type of combination horizontal coke-oven whereinheating-fines of a heating-wall are communicably connected with acorresponding group of heating-fines in an adjacent heat-ing-wall bymeans of crossover duct means that extend over thetop of theintermediate coking-chamber. The coking-chambers [0 are formed betweenspaced heating walls that extend transversely of the battery andcomprise a multiplicity of vertically disposed heating-flues II, theheating-Hues of each heating-wall being operatively divided intoflue-groups of which each communicates by means of a crossover duct 12with a corresponding group of heating-fines in an adjacent heating-wall,and the so-connected fluegroups alternate periodically a flame-flues andcombustion-products flues. Each heating-flue at its lower partcommunicates individually with a source of rich fuel-gas and with a pairof regene erators that are separated by and are adjacent opposite sidesof a pillar-wall l3 which supports the flued heating-wall thereabove.These regenerators, l4, l5, that extend transversely the entire width ofthe battery, at their upper parts are provided with conduitsrespectively 5, II, whereby each heating-flue of the heating-wall abovecommunicates individually with said regenerators, and said conduitsmerge a short distance below the bottom of each flue into a common ductl8 that operates as their heating-flue inlet. eflective opening of saidduct is regulated by portcore l9 that is replaceably mounted atop-thatportion of the capital of pillar-wall I3 which serves to form thedividing wall between the inclined said ducts 16, ll. Rich fuel-gas, atsuch times as the illustrated battery is heated by its combustion, isintroduced into the outer end of a duct 20 that extends the full lengthof a pillar wall l3, wherein it is formed, and is apportioned to all theheating-flues of the above heating-wall by means of upwardly-extendingbranch-conduits 2| and of calibrated nozzles 22, each said conduit andnozzle being individual to aheating flue. During said rich-gasunderfiring, the flame-fines are supplied with air for combustion fromboth of the regenerators I4, l5 that are located directly therebeneath,and their combustion-products are delivered to the battery-stack throughanother pair of adjacent regenerators l4, I5 that communicate with thesame common crossover duct l2. During preheated lean-gas underfiring,

upfiow regenerators [4 are adapted to receive, in-.

stead of air, lean fuel-gas from an outside reservoir therefor throughtheir sole-channels 23 and to preheat said gas prior to its delivery totheir associated flame-flues, Whereas the adjacent upfiowingregenerators I5 still serve to preheat the air required for itscombustion; at such times as their directly associated heating-flues areoperating as downflow heating-fines, all the regenerators l4, l5, serveto carry combustion-products to the battery stack (not shown). During aregenerative heating-cycle in the illustrated battery, all theheating-fines in the same heating-Wall function simultaneously either asflame-fines or combustion-products flues.

Combustion-products, formed' by the combustion of the employedheating-gas and air in the flame-fines, flow upwardly therein and allthe combustion-products from all the heating-fines comprising aheating-wall fluegroup commingle at their tops in a common horizontallextending conduit-like opening 3| whence they pass into crossover ductI2 and over the top of an intermediate coking-chamber into acorresponding group of heating-fines in an adjacent heating Wall ontheir Way to the battery stack.

Coal that is to be carbonized in coking-chambers I0 is introducedthereinto at their tops through charging-holes 25 in the well-knownmanner, after which it is levelled by reciprocation, throughleveller-opening 26 of oven-door 21, of a leveller-bar that is supportedon a pushermachine for the battery.

Heat evolved in the fiame-flues by said combustion of heating-gas andair therein is absorbed into their masonry and is transmitted into the.coal, that is charged into the coking-chambers,.

by those portions of the heating-flue and the entire heating-systemmasonry that form side-walls The 28, the roofs 28, and the bottoms ll ofsaid cokins-chambers. Sufficient heating-gas is burned in theheating-flues to cause the coking reaction to penetrate fromcoking-chamberside-walls 28 into the oven-charges at the rate of aboutone half inch per hour from each said side-wall.

The coal-coking reaction comprises a rather complex sequence of physicalphenomena and includes, in a freshly charged coke oven, the initialfusion at a relatively low temperature of a narrow band or layer of coalthat is either directly in contact with the hot choking-chamber surfacesor is subjected to direct radiation therefrom. This band or layer offused coal is variously referred to in the coking art as the plasticzone" or the tar-seam. Continued heating of the fused band or layer ofcoal brings about, as its temperature increases, decomposition of thefused constituents and an evolution therefrom of gases and vapors andthis phenomenon is followed by a solidification and cementation of thenonvolatilized residue of said fused zone into the substance known ascoke." As the coking reaction progresses through an oven-charge over aperiod of many hours and before its complete conversion to coke, saidoven-charge presents, an outer surface or rind of solidified coke thatis increasing in thickness with continued heating,

an inner core of unfused coal that is becoming narrower and narrower,and an intermediate band or zone of fused coal which grows gradually oflesser and lesser periphery as the center. of the oven-charge isapproached but remains always approximately of the same relatively minorthicknessless than about one inch. Inasmuch as most coking coals fusebelow about 500 C. and the heated surfaces of the masonry of thecoking-chamber walls are atincandescent heat, the zones of plastic coalprogress toward the center of the oven-charge in fused bands that existmore or less in parallelism with the adjacent hot coking-chambersurfaces including the top and the bottom; in result, these fused zonestogether form a sort of continuous envelope that entirely surrounds theinner core of uncoked coal and is intermediate such core and the cokedouter rind of the coal-charge until all parts of said zones merge at thecenter of the oven-charge. The degree of plasticity obtaining in thezone of plasticity during the period when its fused components aredecomposing into gases and vapors is very important both for success ofcoking operations and the integrity of the cokeoven structure. Somecoals and mixtures thereof exhibit such rather high viscosity in theirplastic seams, during the time when gases and vapors are being evolvedtherefrom, that said gases and vapors can escape only after they haveaccumulated therein under relatively high pressure: this internalpressure in the oven-charges is transmitted to the coking-chamber wallsand in the instances of some bituminous coals exhibits sumcient pressureto cause permanent misalignment of the masonry of the heating walls. Inthe cases of coals that show this tendency to exert more than apreferred amount of pressure against the oven-masonry, it has been foundexpedient for alleviating this eventuality to coke them at somewhatslower than normal coking rates; that is, coking the charged coalthroughout all parts of the oven -charges more slowly than at the usualfaster coking rates makes it possible for the gases and vapors ofcarbonization to volatilize from said ovencharges at reduced andpermissible pressures 6 therein. Such expedient is ahardly-to-be-observed practice in modern coking installations because itseriously limits the output of costly coke plants and prompts coke-ovenmanagers to employ predominantly those coals, or coal mixtures, thatexhibit a relatively high degree of fluidity during their fusion-phasesand are consequently coked without special precaution in their heating.

Those hot gases and vapors of the coal distillation which create theinternal pressure in the oven-charges are primarily those that have atendency to evolve at the cooler coal-side of the levels of theoven-charges depends, amongst other factors, on the relative amounts ofcoal thereadjacent to absorb the available heat from the masonry; thatis, the wider the layers of coal forming the tops of the oven-chargesthe more coal there will be there present to absorb the heat deliveredthereto from the adjacent masonry and consequently the morev easy is theapparent penetrability of the plastic zone main tained at the ovenlevel; and, in result, the gases and vapors flowing upwardly through theaforesaid uncoked core of the oven-charges escape from the plasticenvelope with less pressure-development and therefore impose lesspressure on the coking-chamber walls.

One of the salient advantages of the present improvement in theconformation of cokingchambers of horizontal coke ovens results from thefact that in the practice the plastic envelope of fused coal is therebyautomatically maintained selectively more apparently penetrable in thetop relatively minor portions of the coalcharges, and the gases andvapors of the distillation process can pass therefrom into thegascollecting spaces at internal pressures less than obtains in thosecoking chambers where the tops of the coal-charges are substantially thesame width as their lower parts; this feature is especially advantageousfor the coking of those coals, or mixtures thereof, exhibiting arelatively low degree of fluidity during their plastic phases because arelatively easily penetrable escape route for the evolution of gases andvapors is contin uously maintained at the tops of the coalcharges andthe preponderance of their content of coal can be coked at coking timesas fast as preferred because of this novel pressure-controllingsafety-valve in the tops of the coal-charges.

According'to the present invention, side-walls 28 of coking-chambersiii, in the illustrated battery, are vertically disposed throughoutsubstanviding in the upper parts of the coking-chambers greatercoal-containing capacity per unit of the coking-chamber height thanobtains in those parts of the coking-chambers that are directly adjacentthe primary combustion-zones of heating flues H so that the charged andlevelled coking-chambers contain at their tops more coal per unit ofheight than obtains in the lower parts thereof, and complete penetrationof coking-heat through the wider upper parts of the coal-charges isdelayed beyond that in the re- 'mainder thereof a period of time that isin direct relationship to the amount of provided topflare; for example,if the coking-chambers are two inches wider at the top than the bottom,complete coking of the coal adjacent gas-col-- lecting spaces 32 isdelayed about two hours after the remainder of the oven-charge is coked.In consequence of the fact that the gas-collecting space 32 is formed ofa greater width of coal than the lower major part of an oven-charge, theheat radiated to such coal from the ovenroof and the uppercoking-chamber side-walls is absorbed by a relatively larger proportionof coal than is provided at such levels in the prior art and, in result,the tops of the coking-chambers are automatically maintained relativelycooler than heretofore and the plastic seams that are developed thereinare automatically maintained relatively more penetrable, therebyfacilitating the evolution therefrom of the volatile products ofcarbonization.

The present improvement in coking-chambers for horizontal coke ovens isof extensive utility in the coking art and provides advantages inoperation and in operating results when employing coking coals, ormixtures of coals, chosen from the whole range of volatile-mattercontents and plasticity characteristics identifying them. The

top of the coal-charge that is formed by normally charging and levellingthe coking-charge of invention yields oven-charges having substantiallyvertical sides that are of the same width from the oven-soles up to aregion adjacent the termini of the heating fiues where they are cappedby a layer of coal that is wider than the remainder of the charge,thereby providing for the lower wall of the gas-collecting space a widerthan normal expanse of coal and consequently a greater than normalamount of coal for absorbing heat, from the adjacent masonry and fromthe hot distillation gases flowing therethrough to the stand-pipe 34whereby they leave the cokingchamber and all of which promotesmaintenance of cooler tops for the coal-charges. The resultant widerthan normal gas-collecting spaces makes the roof-carbon problem lessimportant of attention in the coking of high-volatile coals becausethere is less inclination for such carbon to restrict the width of thecoal surface forming the lower wall of the gas-collecting space to lessthan that of the lower part of the oven-charge and thus reduces thetendency such condition has to promote the condition known as hot-tops"and inhibits the cracking of desirable liquid products before they haveeven left the coking-chamber. In the case of coals havin a tendency todevelop during their high-temperature coking, higher than preferredinternal pressures that are transmitted to the coking-chamber walls, thepresent development is of important advantage since it provides meanswhereby of those highly viscous plastic seams that always develop in theoven-charges along zones that are adjacent to and substantially parallelthe different heating surfaces of the coking-chambers, one such seam canbe maintained of greater apparent penetrability to gases and vapors thanthe others, thereby providing an outlet of lower resistance topenetration for volatile products evolving from the center of thecoal-charges and thereby reducing the tendency to build up internalpressure in the coal charge and making faster coking-times practical forsuch coals because the degree of fluidity existing in the elastic zonesin the other portions of the coal-charges become relatively unimportant.The novel effects made possible by the instant improvements for alltypes of coking coals can be further enhanced, for example, by forminthe wider capping layer of coal of a higher bulk density than obtains inthe remainder of the oven-charge, or by forming it of wet coal havingpreferably more than about ten percent of free moisture, and therebystill further increasing the additional time that is required forcomplete coking of the capping layer of said coalcharges which can beformed with their novel configuration either by flowing coal into theimproved coking-chambers or by forming said charges as stamped cakesoutside the battery structure and thereafter introducing said cakes intoand coking them in coking chambers having substantially the samecontour.

The invention as hereinabove set forth is embodied in particular formand manner but may be variously embodied within the scope of the claimshereinafter made.

I claim:

1. The improved method of producing hightemperature coke in a horizontalcoke oven, said method comprising: forming an oven coal-charge forcoking in said oven, prior to coking therein, as a horizontallyelongated mass of coal with two opposite vertically disposed sides anduniform widthfrom the bottom thereof upwardly throughout the majorportion of its total height, and with a top levelled overhangingcappinglayer of coal that is a minor portion of the total height of saidmass but which is throughout the horizontal length of the mass, widerthan, and projects over the two opposite sides of, the lower said majorportion; the oven charge being performed to a total height, and the topof the capping layer being levelled, to leave above its top surface, asthe top level for the levelled oveneoal-charge, a likewise overhanginggas collecting free-space extending horizontally along over said toplevel lengthwise beneath the crown of the coking chamber, through whichthe distillate gas may flow off from the charge, when underlying below,horizontally along the crown of the oven over the underlying levelledoven charge, during coking therein; and the top of the capping layerwhich, as the top level for levelled coal charges, is to be contiguousto the overlying gas-collecting ofiflow crown space being formed of atransverse width wider in a horizontal plane than the width of theportions of the oven' charge at levels below the overhanging cappinglayer; thereafter coking the oven charge, while still soformed, in saidhorizontal coke oven, and withdrawing the distillate gas off coolerhorizontally through the gas-collecting space left above said charge,while still so-formed, while maintaining the gas-collecting space in theregion where the top of the levelled coal charge is contiguous to thegas ofiflow crown space unobstructed to diffusion of gas from side toside and of an effective free cross-sectional area, transversely of thecoking charge, greater than that of the area of the portion of the coalcharge below the capping layer; and effecting the aforesaid coking ofsaid oven charge by flowing hot combustion-products into indirectcontact with the said lower major portion of said mass of coal along itstwo opposite sides from the bottom thereof upwardly and therebyabsorbing coking-heat into said mass of coal and coking it; andsimultaneously flowing hot combustion-products of a lower temperaturethan those employed for heating the lower portion of said mass of coalinto indirect contact with its upper minor portion of saidwidercapping-layer and absorbing coking heat thereinto so that the coal inthe lower major portion of the mass of coal is completely coked beforethat in its said upper minor capping layer and thereby preventing, inconjunction with the dissipation of heat in a wider area of coalparticles in the region contiguous to the gas offflow space, throughoutthe major portion of the coking period, overheating of the volatileproducts of the coking reaction continuously passing into and on throughthe gas-collecting space upon its evolution from the top of said coalmass.

2. The improved method of producing hightemperaturecoke in a horizontalcoke oven, said method comprising: forming an oven coal-charge forcoking in said oven, prior to coking therein, as a long, high, andnarrow bed of coal of uniform width from the bottom thereof upwardlythroughout the major portion of its total height, and with a toplevelled overhanging cappingiayer of coal that is a minor portion of thetotal height of said bed but which is throughout the horizontal lengthof the bed, wider than, and projects over the opposite sides of, thelower said major portion of the bed; the oven charge being preformed toa total height, and the top of the capping layer being levelled, toleave above its top surface, as the top level for the levelled ovencoalcharge, an overhanging gas-collecting freespace likewise projecting overthe opposite sides of the lower major portion of said bed and extendinghorizontally along over said top level lengthwise beneath the crownofthe coking chamber, through which the distillate gas may flow oil fromthe charge, when underlying below, horizontally along the crown of theoven over the underlying levelled oven charge, during coking therein;and the top of the capping layer which, as the top level for levelledcoal charges, is to be contiguous to the overlying gas-collectingoffflow crown space, being formed of a transverse width wider in ahorizontal plant than the width of the portions of the oven charge atlevels below the overhanging capping layer; thereafter, while the ovencharge is still so formed, coking the same in said horizontal coke oven;continuously passing the volatile products of the coking reactionevolving from said coal bed into the upper gascollecting space; andwithdrawing the distillate gas of! horizontally through thegas-collecting space left above said charge, while maintaining thegas-collecting space, in the region where 'the top of the levelled coalcharge is contiguous i0 area of the portion of the coal charge bed belowthe capping flayer.

3. The improved method of producing hightemperature coke in anintermittent coke oven, said method comprising: forming an ovencoalcharge for coking in said oven, prior to coking therein, as ahorizontally elongated high, and narrow bed of coal with a top levelledoverhanging offset capping-layer of coal that is a minor portion of thetotal height of said bed but which is throughout the horizontal lengthof the bed, wider than, and projects as an offset over at least one ofthe high sides of, the lower portion of the bed; the oven charge beingpreformed to a total height, and the top of the capping layer beinglevelled, to leave above its top surface, as the top level for thelevelled oven-coal charge, an overhanging offset gas-collectingfree-space likewise having its offset projecting over the same side thatthe capping layer is offset, and extending horizontally along over saidtop level lengthwise beneath the crown of the coking chamber, throughwhich the distillate gas may fiow off from the charge, when underlyingbelow, horizontally along the crown of the oven over the underlyinglevelled oven charge, during coking therein; and the top of the cappinglayer which, as the top level for levelled coal charges, is to becontiguous to the overlying gas-collecting ofiflow crown space, beingformed of a transverse width wider in a horizontal plane than theportions of the oven charge at levels below the overhanging cappinglayer; thereafter coking the so-formed oven charge while it is still soformed, in said horizontal coke oven, and withdrawing the distillate gasoil through horizontally through the gas-collecting space left abovesaid charge as it evolves from the charge, while maintaining thegas-collecting space unobstructed to diffusion of gas from side to sideand of an effective free crosssectional area, transversely of the cokingcharge, greater than that of the area of the portion of the coal chargebed below the capping layer.

4. The method according to claim 2 characterized by a capping layer ofhigher bulk density than the lower major portion of said bed of coal.

5. The method according to claim 2 wherein said capping layer has ahigher moisture content to the gas oifflow crown space, unobstructed todiffusion of gas from side to side and of an effective freecross-sectional area, transversely of the coking charge, greater thanthat of the than the lower major portion of said bed of coal.

JOSEPH BECKER.

REFERENCES CITED The following references are of record in the. file ofthis patent:

UNITED STATES PATENTS Number Name Date 659,048 Atwater Oct. 2, 19001,025,419 Moss May 7, 1912 1,650,127 Perry Nov. 22, 1927 1,707,427Becker Apr. 2, 1929 1,986,007 Vobach Nov. 14, 1933 2,018,604 Flt! Oct;29, 1985

